1. Field of the Invention
The present invention relates to communication terminals which are connected to a communication network through a data channel for transfer of such data as line transaction data or packet transaction data and through a signal channel for control of a call to a communication destination party, and more particularly, to a communication terminal apparatus which can realize effective communication processing on the basis of proper identification of subscriber numbers or subaddresses received or transmitted through the signal channel as identification data.
2. Description of the Related Art
In prior art communication networks, a data channel for transfer of transaction data is separated from a signal channel for transfer of control data as mentioned above so that, for example, the control data can always be transmitted through the signal channel independently of voice or picture data as the transaction data or control of a plurality of such data channels can be established through the single signal channel, whereby different sorts of services including telephone, telex and facsimile can be efficiently and integrally realized. One of these prior art communication networks is, as well known, an ISDN (Integrated Services Digital Network).
In the ISDN, the above data channel is referred to as the B channel and the above signal channel is referred to as the D channel. Through the D channel of the signal channel, in particular, identification data on caller communication terminals can also be transmitted as control data. Accordingly, a communication terminal to be called can know, on the basis of the identification data of the caller communication terminal received through the D channel, one of the communication terminals which issued the transmission data (voice or picture data) of the B channel. The identification data includes subscriber numbers previously designated to subscribers of the communication network and subaddresses arbitrarily set among some of the subscribers as additional data to the subscriber numbers. The subaddresses, which are attached to some of the subscriber numbers as necessary, are used, for example, when it is desired to specify one of a group of terminals (user in-home facilities) to which a common subscriber number is designated.
Such ISDN can indeed realize such various sorts of services as mentioned above integrally and efficiently and also can allow the signal-received (receiver) communication terminals to recognize the caller communication terminal on the basis of the identification data of an incoming signal received from the D channel. In the prior art communication terminal apparatus connected to the ISDN, however, the identification data has been used only for the purpose of the recognization or identification of the caller terminal and processing, control and so on concerning the actual communication have been separately carried out through operator's control panel. As a result, the ISDN has not fully been utilized in overall communication efficiency.
For example, the following utilization forms (a) to (e) are highly important for the purpose of realizing improved user interface as a communication terminal apparatus and thus realizing a high communication efficiency of the overall communication network. However, it has been impossible for the existing communication terminal apparatus, even how it is connected to the ISDN, to realize these utilization forms.
(a) Transaction data sent from the specific communication terminal can be automatically transmitted to another specific communication terminal.
(b) The operator at the communication terminal to be called can immediately know the caller subscriber (caller communication terminal).
(c) The specific communication terminal can be automatically set in its specific mode independently of the communication protocol.
(d) When the communication terminal to be called is in its communication disable state and later the state is removed, a message indicative of removal of such state is automatically sent to the caller communication terminal.
(e) Arbitrary incoming-signal reception conditions are set with use of the above identification data and arbitrary incoming-signal reception control is carried out on the basis of the satisfaction or unsatisfaction of the conditions.